AR-10 Explained: DPMS High vs Low Profile vs Armalite Pattern

Why the AR-10 has no single standard

The AR-15 has a mil-spec that almost every maker follows. The .308 AR never got one. Armalite built the original AR-10, then DPMS made its own LR-308 design, and other makers copied one or the other.

Today most aftermarket parts follow the DPMS pattern, but even DPMS comes in two shapes. Knowing which one you have saves you from buying a handguard or barrel that does not fit.

DPMS high profile vs low profile

Both DPMS types use the same LR-308 barrel nut threads and the same barrel extension. The difference is the upper receiver itself: the height of its top rail. DPMS changed the rail height around 2009, so older and newer designs differ, and other makers picked one or the other.

That height matters most for the handguard. A handguard is built so its top rail lines up with the upper's rail. A low-profile handguard can go on a high-profile upper, but the rails will not line up evenly, which is a problem if you want to run an optic or mount across the gap.

Common examples: the Aero Precision M5 family is high profile. Many billet uppers, such as the Luth-AR and several side-charging designs, are low profile. In the AR-10 Studio every upper and handguard is tagged DPMS high or DPMS low, and the studio warns you when they don't match.

Armalite pattern

Armalite-pattern rifles are their own system. The Armalite AR-10 uses a different barrel nut (1-7/16 x 18 threads) and a different barrel extension, so LR-308 handguards and barrels do not fit.

Uppers and lowers also don't cross between Armalite and DPMS, even when the pins look close. An Armalite barrel will not headspace correctly in a DPMS upper, and the other way around. That is a safety problem, not just a fit problem.

If you own an Armalite, shop for parts made for the Armalite AR-10 by name, and check your rifle's manual before buying magazines, since older Armalite rifles used their own.

Parts that are mostly shared

Charging handles are pattern-specific. The ones in the studio are DPMS pattern.

Magazines: SR-25 pattern magazines like the Magpul PMAG LR/SR are the common standard for DPMS-pattern lowers.
Barrels: the .308 family (.308, 6.5 Creedmoor, .243, 6mm Creedmoor, .338 Federal) all use 5/8x24 muzzle threads in the studio.
Grips and triggers: most AR-15 grips and fire control groups fit AR-10 lowers too.
Stocks: AR-10s use AR-15 style stocks on the tube, but need an AR-10 buffer and spring.

How to tell what you have

The easiest way is the maker's spec page, which usually says DPMS high, DPMS low, or Armalite. If you can't find it, contact the maker with the model or serial number. Guessing from photos is unreliable.

For a new build, the safest route is to buy the upper, lower and handguard as a matched set from one maker, or pick parts that list your exact pattern.

A simple matched build

High profile: Aero Precision M5 stripped upper (about $140) with an Aero M5 ATLAS S-ONE 15 in handguard (about $225).
Low profile: Luth-AR DPMS low profile upper (about $125) with a Midwest Industries DPMS Low 15 in Combat Rail (about $210).
Armalite: ArmaLite A-Series stripped lower (about $227) with an ArmaLite M10 TAC 15 in handguard (about $170).
Shared: Magpul PMAG 20 LR/SR (about $18) and a Geissele 7.62 Super Charging Handle (about $125) for DPMS builds.

Build it

Open the AR-10 Studio, pick your upper first, and let the fit checks filter the rest. Have a gunsmith check headspace on any new barrel and bolt pairing. Prices are rough street prices and change often, so check current listings before you buy.

Parts in this guide

Aero Precision M5 (.308) Stripped Upper Receiver

$140 · Upper receiver

Aero Precision M5 .308 ATLAS S-ONE M-LOK Handguard, 15"

$225 · Handguard

Luth-AR .308 Stripped Upper Receiver, DPMS Low Profile

$125 · Upper receiver

Midwest Industries AR-308 Combat Rail M-LOK Handguard, DPMS Low, 15"

$210 · Handguard

ArmaLite AR-10 Stripped Lower Receiver (A-Series)

$227 · Lower receiver

ArmaLite AR-10 M10 TAC M-LOK Free-Float Handguard, 15"

$170 · Handguard

Magpul PMAG 20 LR/SR GEN M3 7.62 NATO, 20 Round

$18 · Magazine

Geissele Automatics 7.62 Super Charging Handle (SCH)

$125 · Charging handle

Open the AR-10 builder

Prices are typical and change often. This guide is general information, not legal advice. Suppressors and short-barreled rifles are NFA items; check federal, state and local law.